Molded filament coating die

ABSTRACT

A one-piece molded coating die for removing excess fluid material from a filament passing along a generally vertical axis through the die is disclosed having upwardly extending side wall portions and a floor and a roof each lying generally transverse to the axis and interconnected by the side wall portions. The floor and roof are provided with threading slots extending generally along a plane including the axis to connect that axis with the die exterior so that a filament may be passed laterally from the die exterior to the axis.

United States Patent [191 Couture MOLDED FILAMENT COATING DIE [76] Inventor: Warren A. Couture, 4916 So.

Wayne Ave., Fort Wayne, Ind. 46807 [22] Filed: June 21, 1974 [21] Appl. No.: 481,511

[52] US. Cl. 118/125 [51] Int. Cl. B05C 11/02 [58] Field of Search 118/100, 123, 125; 1 17/102 L [56] References Cited UNITED STATES PATENTS 2,238,575 4/1941 Alexay 118/125 2,238,687 4/1941 Flynn 118/125 2,309,057 l/l943 Flynn 118/125 2,438,700 3/1948 Hoban 118/125 Aug. 12, 1975 3,110,625 11/1963 Bettner 118/125 Primary ExaminerMervin Stein Assistant ExaminerDoug1as Salser Attorney, Agent, or Firm-Albert L. Jeffers; Roger M. Rickert [57] ABSTRACT A one-piece molded coating die for removing excess fluid material from a filament passing along a generally vertical axis through the die is disclosed having upwardly extending side wall portions and a floor and a roof each lying generally transverse to the axis and interconnected by the side wall portions. The floor and roof are provided with threading slots extending generally along a plane including the axis to connect that axis with the die exterior so that a filament may be passed laterally from the die exterior to the axis.

6 Claims, 8 Drawing Figures PATENTED AUG 1 2|975 MOLDED FILAMENT COATING DIE BACKGROUND OF THE INVENTION The present invention relates to a die for coating or treating a filament of material and more particularly to such a die for applying a controlled amount of a liquified insulating material to a conductive wire. As used herein, the term filament" is intended to include such conductive wire in round, square, or rectangular cross sections as well as all other elongated solid or standard strips, threads, and the like suitable for coating.

It is known in the priorart to coat a filament, such as magnetic wire, with an insulating material by applying an excess amount of insulating material in a fluid state to the wire and draw the wire upwardly through a wire coating die of one of the types disclosed in US. Pat. Nos. 2,238,575; 2,309,057; 2,407,337; and 3,110,625, which wire coating die functions to wipe off excess fluid insulating material leaving approximately the desired amount of fluid insulating material on the wire to solidify forming an insulated conductor.

A modification of the wire coating die disclosed in the aforementioned United States patent has also been employed in coating magnet wire, which modification eliminates the wire coating bushing and simply places the aperture of that bushing in the upper portion of the metallic structure.

The prior art wire coating dies are characterized by complex forming steps and attendant problems as well as rapid wear out and frequent replacement requirements. The elastic limits of the metallic coating dies are frequently exceeded either when threading wire through the die or during othr handling and are easily crushed, for example, by the inadvertent application of a shoe.

It is accordingly a general object of the present invention to provide an improved filament coating die.

An object of the present invention is to provide a wire coating die characterized by its ruggedness and economy of manufacture.

Another object of the present invention is to provide a wire coating die which gives controlled and uniform insulation thickness.

A further object of the present invention is to provide a one-piece molded wire coating die thereby opening the possibility of molding a number of such dies simultaneously.

Yet another object of the present invention is to provide a filament coating die of extended life by both reducing the chance of mechanical damage, and reducing wear of the filament coating aperture.

SUMMARY OF THE INVENTION The foregoing as well as numerous other objects, features and advantages of the present invention are achieved by providing a one-piece molded wire coating die for removing excess fluid insulating material from a conductive wire passing along a generally vertical axis through the die, having a pair of upstanding side walls,

a floor and a roof with the floor and roof lying generally transverse to the axis and interconnected by the up:

standing side walls to enclose a die support opening extending transversely to the axis with the roof being provided with a wire threading slot extending through less than the entire roof generally along a plane including the axis to connect that axis with'the die exterior so that wire may be passed laterally from the die exterior to the axis. The underside of the floor, remote from the roof, is concave opening downwardly for an improved gross wiping action and the roof has a smaller aperture coaxial with the axis for providing a later fine fluid wiping action.

The subject matter which I regard as my invention is particularly pointed out and distinctly claimed in the concluding portion of this specification. My invention itself, however, together with further objects and advantages thereof may best be understood by reference to the following description taken in conjunction with the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 illustruates in perspective the molded wire coating die of the present invention with die support fingers shown in dotted lines in the relative position assumed during a wire coating operation;

FIG. 2 illustrates the molded wire coating die in perspective with the underside of the die floor visible;

FIG. 3 is a top view of the molded wire coating die;

FIG. 4 is a side view of the wire coating die;

FIG. 5 is a bottom view of the wire coating die;

FIG. 6 is a front view of the wire coating die;

FIG. 7 is a cross section view along the line 7-7 of FIG. 4; and

FIG. 8 is a cross section view along the line 8-8 of FIG. 5.

DESCRIPTION OF THE PREFERRED EMBODIMENT In FIG. 1 where the top, front and side of the molded wire coating die are visible the die is seen to be formed as a one-piece molded non-metallic coating die for removing excess fluid material from a filament passing along a generally vertical axis through the aperture 11. The die comprises a pair of upstanding side walls 13 and 15 which interconnect a roof 17 and a floor 19. The side walls, roof and floor form a die support opening 21 through which die support arms 23 and 25 pass in a direction generally transverse to the wire axis. The die support arms 23 and 25 are also sometimes referred to as die support fingers. In use, wire is pulled upwardly through the wire passing fluid wiping aperture 11 so that the die is urged upwardly and held in the position illustrated by the die support arms resting against the lower support shoulders of the die support opening. When the die is not in use it rests with the upper support shoulders of the die support opening resting on top of the die support arms 23 and 25.

It would be feasible, but generally difficult, to thread wire or other filaments into the die by passing the wire axially along the wire axis and to aid threading the front surface of the roof 17 is provided with a wire threading V, or V-shaped notch 27 having an apex 29 which communicates with a wire threading slit 31. This wire threading slit extends through less than the entire roof, generally along a plane including the wire axis and connects that wire axis with the die exterior so that wire may be passed laterally from the die exterior to the wire axis. To aid in passing this wire from the die exterior to the axis, an expansion slot 33 is provided and the wire threading slit extends beyond the wire axis to the expansion slot 33. The expansion slot 33 of course extends through the roof 17.

Asimilar but larger threading slot 35 is provided in the floorand extends generally along the same plane as the wire threading slit 31. The floor of the die also has a wire passing fluid wiping aperture therein comprising the central portion of the slot 35 which is generally coaxial with the wire axis. This floor aperture provides a first gross fluid wiping action on the adhering column of insulating material afte which a second or later fine fluid wiping action is effected by the wire aperture 11. The underside of the floor l9, remote from the roof 17, is concave opening downwardly for an improved gross wiping action. A similar type effect is achieved for the upper cylindrical wire aperture 11 by providing an inverted V-shaped slot in the underside of the roof extending generally transversely to the wire axis and communicating with the cylindrical opening 11 which is coaxial with the wire axis. The peak of the inverted V lies along the wire threading slit.

In operation wire is passed upwardly through a source of liquified insulating material with the material adhering to the wire forming an upwardly moving column of liquid insulating material around the wire which column is partially wiped away by the underside of the floor as the wire and adhering insulating material pass through the gross wiping aperture in the floor of the die. Thus the column of liquid insulating material may include both upwardly and downwardly moving liquid. The gross wiping die removes or wipes away less than the optimum quantity of liquid so that the wire and remaining adhering insulating material pass upwardly to the roof of the die where a second wiping action occurs and the wire as it leaves the cylindrical wire aperture 11 retains the desired quantity of insulating material which subsequently due to evaporation and curing solidifies forming the insulated wire as desired. The liquid insulating material which is wiped from the wire and liquid column by the upper or fine wiping aperture passes back downwardly and out of the die through the relief ports 37, 39, and 40, and additionaly some liquid may flow through the wire threading slot 35 back downwardly to rejoin the larger liquid column. By providing these relief ports 37, 39, and 40, the die tends to prevent any liquid flow along the die support arms 23 and 25 thus keeping dripping to a minimum.

In its preferred form, the die is molded in one piece from a thermoplastic resin and more specifically from a fluoroplastic such as chlorotrifluoroethylene which is normally available as a homopolymer or as a copolymer with vinylidene fluoride and other monomers added to improve processability.

Thus, while the present invention has been described with respect to a specific preferred embodiment in both die structure and use, numerous modifications will readily suggest themselves to those of ordinary skill in the art. While a fluoroplastic is a preferred material for the onepiece molded wire coating die, many other plastics or rubber materials having specific gravities varying between 0.7 and 2.3 may be used in specific die applications. Among other things the specific die and material for a specific application will be determined in part by tensile, compressive and flexural strength as well as creep properties and the material s resistance to temperature of liquids or air and the effect of organic and inorganic solvents, strong and weak acids and alkalis and the thermal properties such as melting point, deflection temperature, softening point, deformation under load and others will dictate the materials and construction. The choices depend, of course, in part on the type of material being applied to the filament which includes a wide range of solids in solvents in varying concentration, either heated or unheated and, for example, may include varnishes, enamels, thermoplastics, glues, waxes, sizings, and oils. In some instances, for example, to coat extra heavy wire, longitudinal paper wrapping or textile, the die base and skirts on sidewalls may be deleted to form a domed or ball die. Thus, while the present invention has. been described with respect to a preferred embodiment various modifications will suggest themselves to those of ordinary skill in the art and accordingly the scope of the present invention is to be measured only by that of the appended claims.

I claim:

l. A one-piece molded wire coating die for removing excess fluid insulating material from a conductive wire passing along a generally vertical wire axis through the die comprising:

upstanding side wall portions;

and a floor and a roof each lying generally transverse to the wire axis and interconnected by the side wall portions, the floor and roof each having a wire passing fluid wiping aperture therein, the floor aperture adapted to provide a first gross fluid wiping and the roof aperture adapted to provide a later fine fluid wiping, the underside of the floor remote from the roof being concave opening downwardly for improved gross wiping action and the underside of the roof configured as an inverted V-shaped slot having an apex near the wire axis.

2. A one-piece molded wire coating die for removing excess fluid insulating material from a conductive wire passing along a generally vertical wire axis through the die comprising:

upstanding side wall portions;

and a floor and a roof each lying generally transverse to the wire axis and interconnected by the side wall portions, the roof being provided with a wire threading slit extending through less than the entire roof generally along a plane including the wire axis to connect the wire axis with the die exterior so that a strandof wire may be passed laterally from the die exterior to the wire axis, both the roof and the floor having wire passing fluid wiping apertures each generally coaxial with the wire axis, the floor aperture adapted to provide a first gross fluid wiping and the roof aperture adapted to provide a later fine fluid wiping, the roof aperture comprising an inverted V-shaped slot in'the underside of the roof extending generally transversely to the wire axis and communicating with a generally cylindrical opening in the roof coaxial with the wire axis.

3. The one-piece molded wire die of claim 2 wherein the peak of the inverted V lies along the wire threading slit.

4. The one-piece molded wire die of claim 2 wherein the roof is further provided with a V-shaped notch for aiding and passing wire from the die exterior into the wire threading slit.

5. The one-piece molded wire die of claim 4 wherein the wire threading slit extends from the apex of the V- shaped notch through the wire axis and terminates in an expansion slot passing through the roof.

6. A one-piece molded non-metallic coating die for removing excess fluid material from a filament passing along a generally vertical axis through the die to thereby apply a controlled amount of fluid material to the filament comprising:

upstanding side wall portions; and a floor and a roof each lying generally transverse to the axis and interconnected by the side wall portions, the roof, floor and side wall portions forming a die support opening extending transversely to the axis, the roof and floor each having a filament passing fluid wiping aperture therein, the floor aperture adapted to provide a first gross fluid wiping and the roof aperture adapted to provide a later fine fluid from the die exterior to the roof aperture. 

1. A one-piece molded wire coating die for removing excess fluid insulating maTerial from a conductive wire passing along a generally vertical wire axis through the die comprising: upstanding side wall portions; and a floor and a roof each lying generally transverse to the wire axis and interconnected by the side wall portions, the floor and roof each having a wire passing fluid wiping aperture therein, the floor aperture adapted to provide a first gross fluid wiping and the roof aperture adapted to provide a later fine fluid wiping, the underside of the floor remote from the roof being concave opening downwardly for improved gross wiping action and the underside of the roof configured as an inverted V-shaped slot having an apex near the wire axis.
 2. A one-piece molded wire coating die for removing excess fluid insulating material from a conductive wire passing along a generally vertical wire axis through the die comprising: upstanding side wall portions; and a floor and a roof each lying generally transverse to the wire axis and interconnected by the side wall portions, the roof being provided with a wire threading slit extending through less than the entire roof generally along a plane including the wire axis to connect the wire axis with the die exterior so that a strand of wire may be passed laterally from the die exterior to the wire axis, both the roof and the floor having wire passing fluid wiping apertures each generally coaxial with the wire axis, the floor aperture adapted to provide a first gross fluid wiping and the roof aperture adapted to provide a later fine fluid wiping, the roof aperture comprising an inverted V-shaped slot in the underside of the roof extending generally transversely to the wire axis and communicating with a generally cylindrical opening in the roof coaxial with the wire axis.
 3. The one-piece molded wire die of claim 2 wherein the peak of the inverted V lies along the wire threading slit.
 4. The one-piece molded wire die of claim 2 wherein the roof is further provided with a V-shaped notch for aiding and passing wire from the die exterior into the wire threading slit.
 5. The one-piece molded wire die of claim 4 wherein the wire threading slit extends from the apex of the V-shaped notch through the wire axis and terminates in an expansion slot passing through the roof.
 6. A one-piece molded non-metallic coating die for removing excess fluid material from a filament passing along a generally vertical axis through the die to thereby apply a controlled amount of fluid material to the filament comprising: upstanding side wall portions; and a floor and a roof each lying generally transverse to the axis and interconnected by the side wall portions, the roof, floor and side wall portions forming a die support opening extending transversely to the axis, the roof and floor each having a filament passing fluid wiping aperture therein, the floor aperture adapted to provide a first gross fluid wiping and the roof aperture adapted to provide a later fine fluid wiping, the underside of the die being concave opening downwardly, and the roof being provided with a wire threading slit extending through less than the entire roof along a plane including the vertical axis to connect the roof aperture with the die exterior so that a filament may be passed laterally from the die exterior to the roof aperture. 